perl面向对象入门之处理json数据和rest api in perl

需求：有些已经实现好的Restful API，通过调用Restful API，取出Restful API的返回值中部分key的值。
1)Rest中，每个对象都是1个URL;
这里需要了解perl发送request,以及怎么处理response.
http://www.redmine.org/projects/redmine/wiki/Rest_api_with_perl
http://search.cpan.org/~ether/libwww-perl-6.15/lib/LWP/UserAgent.pm

2)Restful API的返回值是json格式的，也就是python中的嵌套字典
这里需要学习json的知识
http://search.cpan.org/~makamaka/JSON-2.90/lib/JSON.pm

3)产物作为类提供
需要了解面向对象，除此以外还需要了解perl的哈希，数组，循环等基础知识。
http://www.runoob.com/perl/perl-tutorial.html

一、安装perl IDE
    有很多，菜鸟教程也有推荐。这里安装的是Padre
    windows PC上装perl IDE:http://padre.perlide.org/   

二、练习
    就是按照菜鸟教程练习0.5天
    
三、就是根据需求写脚本
每个URL返回的数据结构如下：

构造函数和一些共通的变量

our $web_base_url          = "";
our %web_base_url          = ();
$web_base_url{testBase}  = "this is for URL";
our $ENODEB =  CONSTANT VALUE
our $CABINET = CONSTANT VALUE
our $TELNET = CONSTANT VALUE
our $SWITCH = CONSTANT VALUE
our $MDU = CONSTANT VALUE
our $SYNCHRONIZATION = CONSTANT VALUE
our $SOURCE = CONSTANT VALUE

##############################################################################
# CONSTRUCTOR
# new ( <testplanName> )
# This is the cunstructor for this class
##############################################################################
sub new {
    my $class = shift;
    my (%params) = @_;
    my $self = {
    _baseUrl => $web_base_url{testBase},
    _tpname => $params{tpname}
    };
    $self->{URL} = $self->{_baseUrl}.=$self->{_tpname};
    bless ($self, $class);    
    $self->_setCisAttributes();
    $self->{class} = $class;
    return $self;
}

1.发送get请求，获得responseContent

sub _getResponseContent{
    my( $self,$URL) = @_;
    my $ua = LWP::UserAgent->new(
             protocols_allowed => [ 'http', 'https' ],
             timeout           => 30,
             ssl_opts => { verify_hostname => 0 }
             );
    my $retval = {};
    my $json = JSON->new->utf8;                    
    my $response = $ua->get($URL);
    if ($response->is_error){
        print "Failed to get  data by $self->{URL}
";
        die $response->message;
    }       
    my $content = $response->content;
    $retval = $json->decode($content);
    return $retval;
}

2.分解每个大的item值

sub _setCisAttributes{
    my($self) = @_;
    $self->{testPlan} = $self->_getResponseContent($self->{URL})->{items};
    foreach ( @{ $self->{testPlan} }){
        die "Not find key cfItem_type in element $->{'cfItem_type'} $self->{URL}" unless $_->{'cfItem_type'};
        if ($_->{'cfItem_type'} =~ /$ENODEB/){
            $self->{testRbsHash} = $_;
        }
        if ($_->{'cfItem_type'} =~ /$CABINET/){
            $self->{testCabinetHash} = $_;
        }
        if ($_->{'cfItem_type'} =~ /$TELNET/ and $_->{'cfItem_type'} =~ /$SWITCH/){
            $self->{testSwitchHash} = $_;
        }
        if ($_->{'cfItem_type'} =~ /$MDU/ and $_->{params}->{Master}->{value} =~ /true/){
            $self->{testMduHash} = $_;
            my $test = scalar($_->{params}->{Master}->{value});
        }
        if ($_->{'cfItem_type'} =~ /$SYNCHRONIZATION/ and $_->{'cfItem_type'} =~ /$SOURCE/){                 
            if (exists($_->{relation_list}->[0]->{params_ci_1}->{Value}->{0}->{'Primary sync ref'}) 
            and $_->{relation_list}->[0]->{params_ci_1}->{Value}->{0}->{'Primary sync ref'}->{value} =~ /true/){
                $self->{testPNTPHash} = $_; 
            }
            else                  
            {
                $self->{testSNTPHash} = $_;  
            }
        }        
    }
    return $self;
}

3.取值的共通方法

sub _getCiAttributes{
    my ( $self, $ci, $attribs ) = @_;
    #print "$ci
";
    #print "$attribs
";
    my $ref = "";    
    switch($ci){
        case "$ENODEB" {
            die "Not find ENODEB attributes
" unless $self->{testRbsHash};                
            $ref = $self->{testRbsHash};                        
        }
        case "$CABINET" {
            die "Not find Cabinet attributes
" unless $self->{testCabinetHash};
            $ref = $self->{testCabinetHash};
        }
        case "$TELNET" {            
            die "Not find telnet switch attributes
" unless $self->{testSwitchHash};
            $ref = $self->{testSwitchHash};
        }
        case "$MDU" {
                    die "Not find master Du attributes
" unless  $self->{testMduHash};
            $ref = $self->{testMduHash};
        }
    }
    foreach ( @{ $attribs } ) {
        $ref = $ref->[ 0 ] if ( ref( $ref ) eq 'ARRAY' );        
        $ref = $ref->{ $_ }; 
    }
    return $ref;
}

4.供包外调用的方法,只举一例

sub getSwitchPort{
    #my($funcName) = shift;
    my($self) = @_;
    return $self->_getCiAttributes("$TELNET",['relation_list','params_ci_1','Port']);
}